Grass mowing machines such as greens mowers, fairway mowers and trim mowers are commonly equipped with several cutting units, each cutting unit having one or more rollers that roll in contact with the ground for supporting the cutting unit during operation. The rollers may be vertically adjustable for establishing the height at which vegetation is cut. The rollers also may provide a desirable striping pattern on the turf by pressing down the grass after it is cut. For example, a smooth roller, typically coupled to the rear portion of the cutting unit, may smooth out or flatten the surface of the ground after the cutting unit has passed over it.
Many grass mowing machines have one or more cutting units in a first or front row, followed by one or more cutting units in a second row. Each cutting unit in the first and second rows may be laterally offset from one another so as to pass over and mow adjacent strips of ground. However, if a second row cutting unit's roller overlaps the path of a first row cutting unit, the striping pattern may be marred with roller overlap marks. Smooth rollers may leave overlap marks where rollers on the first and second rows of cutting units push the same grass down. Grooved rollers may leave overlap marks where the first and second rows of cutting units tend to stand the grass up more.
To reduce the overlap marks, some grass mowing machines have shortened the rear rollers. Although shortened rollers reduce the overlap marks, the shortened rollers fail to support the end of the cutting unit sufficiently to maintain a constant height of cut, and also may leave marks where the outside edges of the rollers dig into the turf. Additionally, some grass mowing machines have light weight hollow rear rollers. However, hollow rollers may fail to provide striping patterns that are desired.
It is desirable to reduce overlap marks from rollers on grass mowing machines having at least two rows of cutting units. It is desirable to reduce roller overlap while maintaining a constant specified height of cut.